Piano string bridging device



$1350 27, 19%; W. R KUZELKA 9 L PIANO STRING BRIDGING DEVICE Original Filed April 24; 1957 INVENTOR g A. TTORNEY S Patented Feb. 27, 1940 UNITED STATES PATENT OFFlCE Application April 24, 1937, Serial No. 138,677 Renewed April 8, 1939 8 Claims.

This invention relates to improvements in the supporting and bridging arrangement for the strings of musical instruments and is particularly applicable to piano construction to provide for improved string bridging in a manner to ofier greater freedom to vibration and particularly to provide a bridging assembly materially less affected by warping of the supporting members than are the present types of construction. As a result the tensional adjustments of the springs and proper tonal qualities of the instrument will maintain over materially increased periods of use.

The improved features and advantages of my present invention will be more fully understood by reference to the accompanying drawing wherein like reference characters are applied to the corresponding parts in the several views. It will be understood that the drawing is submitted for the purpose of illustration only and should not be taken as a limitation to the exact embodiments shown. The invention may find expression in various forms within the definition of the accompanying claims.

Referring to the drawing: I

Fig. 1 is a partial plan view of a piano string section where three strings constitute a note and wherein my improvements are incorporated therewith.

Fig. 2 shows in perspective a portion thereof showing my improved lateral bridge and spacing device.

Fig. 3 is a similar view showing a desirable two string modification thereof.

Figs. 4 and 5 are respectively partial plan and vertical sectional views showing a modified form of my invention adapted for lateral tensioning of single string note structure.

Fig. 6 is a partial perspective View showing a modified form of lateral bridge member adapted for three string notes.

In one of the embodiments of the features of my invention as here shown incorporated in a piano construction, I indicates the usual string plate provided with the string anchor pins 2 and at the opposite side 3 indicates the wrest plank member provided with the conventional tuning pins 4. At 5 is shown the metal bridge formed integral with the cast metal member 3 in the usual manner and over which the strings s are passed for tensioning purposes and to determine the vibration zone thereof. At 6 is the conventional pressure bar secured to the member 3 and co-acting with the bridge 5. At 8 is shown the conventional soundboard to which is attached the usual wooden soundboard bridge ID. The foregoing in its general structure conforms to conventional design, the strings being shown having their ends attached to the rotary tuning pins 4 and being looped over the anchor pins 2 as indicated.

It will be understood, however, that the inven tion which resides in the bridging device is not necessarily limited to a musical instrument of the type having a soundboard in which the quality of the tones is enhanced by sympathetic vibration, but it may be applied with equal advantage to the type of instrument in which the soundboard has been replaced by other resonating means or by radio tubes or microphones which pick up and amplify the vibration of the strings through loud-speakers. Thus the invention relating to the bridging device may be applied to instruments wherein the vibration is forced as well as sympathetic. However, since the particular construction of the musical instrument forms no part of the invention; it is not deemed necessary to illustrate it herein.

Provision is likewise made, associated with the lateral bridge ID, for the proper lateral spacing of the strings and which in accordance with my invention provides a bridge effect as related to the tensioning of the strings and of a character to have no restriction of string movement in a direction perpendicular to the plane in which the strings are strung and accordingly to be unaffected in the tensioning effect by any warping of the supporting parts. To this end there are employed bridge and spacing members l2 formed for attachment to the bridge it, for the purpose of three string engagement the bridging member is formed with laterally extending flange or wing portions l3 having perpendicular outer edge surfaces and a perpendicular walled central groove [4 for the central string as shown in Figures 1 and 2 of the drawing. In the three string design of lateral bridge spacers of Figs. 1 and 2, the wing portions I3 are formed with relation to the attaching portion so as to have a slight flexibility or resilience whereby under the tension of the outer strings the wings or prong portions will exert a pressure upon the central'stringpassing through the central opening it.

This desirable formation of the bridge spacers 12, as will be understood, provides lateral bearing for the strings which are elongated in a direction perpendicular to the plane in which the strings are strung, so that the strings'are not restricted in perpendicular movement, thereby to be nonafiected in their tensional adjustment by warping or change of the supporting members. Cooperating therewith, there are provided yoke or clamping members I 5 supported upon the strings in floating arrangement to be likewise unrestricted in perpendicular movement. These clamps l5 bear laterally upon the outer strings and have a reduced width of bearing engagement or spacing relative to the outer bearing surfaces of the bridge members l2 thereby to provide a lateral force and tensioning effect upon the strings as will be appreciated.

In Fig. 3 is shown a modified form of the bridge spacer member adapted for a two string note arrangement. with a central stud for attachment to the bridge I0 and formed with a flattened upper flange portion l6 having opposite, vertical string bearing surfaces l1 providing the laterally disposed bridge bearing surfaces non-restrictive in a vertical plane. So-acting therewith is the clamp 15 in the manner described.

In Figs. 4 and 5 there is shown a desirable modification adapted for single string note arrangements commonly employed in the bass cleft. As illustrated, separate studs 20 are secured in the bridge l0 providing vertical bearings for each of the two strings 8 held in close spacing by the floating clamp 22. The bearing studs 20 are engaged by an interposed truss member 23 formed of interlocked sheet metal members 232 i having registering tongue and groove connection and. functioning to resist lateral deflection of the studs under the tension of the string adjustment.

In Fig. 6 there is shown a further modified form of improved bridge-spacer embodying the features of my invention and having a different method of mounting upon the bridge member. Therein the bridge-spacer member lZis of angular form having a lower, perforated base flange 25 for attachment to the bridge member ID by two wood screws with an interposed pad of buckskin 26 between the sound board bridge and bridge-spacer member l2. The latter is formed with flange providing string bearing outer faces 2! and central disposed bearing walls 28 and the I lower portion of the vertical flange is undercut as shown to allow resilient action of the wing portions to effect tensional gripping of the central string.

As will be appreciated from the foregoing disclosure, I have provided an improved string bridging arrangement retaining to a large degree the conventional bridge control of the vibratory action of the strings with a supplementary laterally acting bridge effect of the bridge-spacer members and wherein the tensional adjustment of the latter will be non-effected by the normal warping of the supporting members by reason of their non-restrictive engagement with the strings along a line perpendicular to the plane in which the strings are strung. An improved and more durable adjustment is thereby permitted with the further important advantage of tonal superiority from the lessened damping effect upon the proper vibration of the strings.

Having described my invention, I claim:

1. In a stringed musical instrument having a sound board and sound board bridge associated therewith, of bridge-spacer members mounted on the latter and interspacing the strings formed for attachment to the bridge and provided with opposite vertical flange portions having .outer vertically elongated string bearing portions and a central, vertical string slot providing vertical In this the spacer is formed string engaging walls whereby the string engagement by the bridge-spacer member will be nonrestrictive to fluctuating vertical string movement and co-acting string clamping members supported upon the strings to position the latter for lateral bridging engagement with the bridgespacer members.

2. In a stringed musical instrument of the character described having a sound board and a sound board bridge associated therewith, of bridge-spacer members mounted on the latter and interspacing the strings, formed with screw portions and opposite, upper flange portions having outer vertical string bearing surfaces and having a central vertical walled string slot therebetween and said flange portions being slightly resilient for clamping effect upon the central string and co-acting string clamping members supported upon the strings to position the latter for lateral bridging engagement with the bridgespacer members.

3. In a stringed musical instrument having a resonating means, a bridging member for interspacing the strings mounted on said resonating means, said bridging member having elongated 1 straight contact surfaces for said strings perpendicular to said resonating means, whereby restrictions of the fluctuations of the strings in a perpendicular direction will be eliminated and binding of the resonating means prevented, and

means for maintaining the strings in frictional contact with saidsurfaces at a point substantially removed from the extremities thereof.

4. In a stringed musical instrument having a resonating means and a sound bridge associated therewith, a bridging member for interspacing the strings mounted on said sound bridge, said bridging member having elongated straight contact surfaces for said string perpendicular to said resonating means, whereby restrictions of the fluctuations of the strings in a perpendicular direction will be eliminated and binding of the resonating means prevented, and means for maintaining the strings in frictional contact with said surfaces at a point substantially removed from the extremities thereof.

5. In a stringed musical instrument having a resonating means, a bridging member for interspacing the strings mounted on said resonating means, said bridging member comprising a pair of opposing wings devoid of contact with said resonating means and having elongated straight surfaces for engaging said strings perpendicular to said sound bridge, and means for maintaining said strings in frictional engagement with said :1:

'7. In a stringed musical instrument having resonating means, a bridging member for interspacing the strings on the instrument, said bridging member comp-rising a pair of opposing wings devoid of contact with said resonating member and having elongated, straight contact surfaces for engaging said strings perpendicular to said resonating means and means for maintaining said strings in frictional engagement with said surfaces at a point substantially removed from the extremities thereof.

8. In a stringed musical instrument, a bridging member for interspacing and supporting the strings on the instrument, said bridging member having elongated, straight, contact surfaces for said strings perpendicular to the plane in which said strings are strung whereby restrictions of the fluctuations of the strings in a perpendicular direction will be eliminated and binding of the strings prevented, and means for maintaining the strings in frictional contact with said surfaces at a point substantially removed from the extremities thereof.

WILLIAM R. KUZELKA. 

